The aim of this essay is to analyze the term saltus in its various acceptations, to try to reconstruct the steps by which, starting from its more generic (and primitive) meaning of uncultivated area covered with woodland, it came to acquire more specialized meanings in the gromatic and agrarian lexicon. Thus, in its wider acceptation the term is used to define impervious and hard to access uncultivated spaces covered with more or less extensive woods. The term, however, was also employed to define other realities. According to Varro, saltus designates a surface which the presence of silvae or other natural obstacles make unsuitable for cultivation, but which can be used
to graze livestock. A slightly later definition of the term is given by Aelius Gallus. Like Varro, Gallus affirm that saltus designates a surface occupied by woods and pastures, but his definition includes a lot more: a saltus houses buildings, workers and surveillance personnel, as well as cultivated area for their sustenance. In this case the term thus appears to refer to a sizable estate with its own autonomous management, which Gallus contrasts with fundus. This contrast reflects two different models of land exploitation, not necessarily complementary:
on the one hand we have specialized transhumant livestock raising carried out at a middle-large scale, on the other agriculture. The connection between saltus and specialized livestock raising also returns in the juridical sources of the early and middle Empire.
In the Republican period, saltus is also used in the gromatic lexicon with a precise technical meaning, to indicate a group of a certain number of centuriae. In the gromatic corpus, the term acquires a new meaning, designating a large estate constituted of several fundi, sometimes extending over an area larger than a town. It is especially the African epigraphic documentation that allows us to form a picture of the organization of these large estates, where the main settlement would sometime take over the civil, religious and economic functions elsewhere performed by towns, and was hence equipped with the necessary civil and religious buildings. Reflections of this new meaning of saltus are found in Italy, in the Veleia table.
These different acceptations progressively taken on by the term can be explained in the light of early interest in the exploitation of uncultivated wooded areas, which, while unsuitable for agriculture, offered mineral, forest and grazing resources. To fully exploit these areas, especially if they were commons, some form of delimitation was needed, both internal, to distinguish individual land grants, and external, to mark the boundary of the saltus with the surrounding property, whether public or private. It is possibly through this process that saltus acquired a meaning in the administrative and fiscal sphere. This would also explain its use in the gromatic lexicon to indicate both a group of a certain number of centuries and a particular type of land concession – in saltibus – within a limitatio, obviously one that did not involve the creation of internal limites in the form of field paths to delimit individual centuries, but simply marking out the limits of the centuries by placing a few cippi along their perimeter. This kind of division may have been preferred for surfaces used for grazing. This would explain the use of saltus in connection with specialized livestock raising, which requires large spaces and hence uses grazing surfaces integrated within the centurial grid, where they are subdivided in saltus, or else uses the ager publicus, which must also have been delimited externally and parceled internally in some way.
It is also possible that the large estates for which the term saltus is employed in the gromatic corpus used a larger-meshed centurial grid, by saltus, which would have provided the cadastral frame of reference. Within each saltus, cippi or other landmarks staked out the centuries or the parcels of tenant farmers and coloni. This could explain why, although the inscriptions of Ain Wassel and Henchir Mettich mention centuriae and subseciva, and thus evoke a gromatically organized area, no remains of centuriation are observable in the middle valley of the Bagradas. If this explanation is correct, saltus would designate a particular form of agrimensory unit used on large estates.